Echini is the plural form of the noun "echinus," which refers to a group of marine creatures belonging to the class Echinoidea in the phylum Echinodermata. Echini are also commonly known as sea urchins.
These organisms are characterized by a round or oval-shaped body covered in a hard, spiky exoskeleton or test made up of calcite plates. The test is divided into five sections or ambulacra, which are marked by rows of tube feet used for locomotion and feeding. The mouth of the echinus is located on its underside and is surrounded by a complex set of muscles and spines.
Echini are found inhabiting the oceans worldwide, from the shallow coastal areas to deep-sea environments. They can be encountered in a wide range of habitats, including rocky reefs, sandy bottoms, and even coral reefs. Their diet mainly consists of algae and other small organisms, which they scrape off surfaces using their specialized feeding apparatus known as Aristotle's lantern.
Echini are important components of marine ecosystems, playing various ecological roles. They participate in the nutrient cycling process, control algal populations, and serve as a food source for many other marine organisms such as birds, fish, and mammals. Moreover, in some cultures, echini are consumed as food due to their high nutritional value.
Due to their unique morphology and ecological significance, echini have attracted scientific interest and have been the subject of extensive research in evolutionary biology, ecology, and paleontology.
